Trinseo (TSE) 8-K Submission of Matters to a Vote of Security Holders

Exhibit 10.1

TRINSEO PLC

AMENDED AND RESTATED

2014 OMNIBUS INCENTIVE PLAN

(as amended June 14, 2023)

WHEREAS:

A.On May 30, 2014, Trinseo S.A., a public limited company (société anonyme) incorporated under the laws of Luxembourg, adopted the Trinseo S.A. 2014 Omnibus Incentive Plan (as so adopted and amended, from time to time, in respect of periods prior to the Effective Time (as defined below), the “Original Plan”).

B.On October 8, 2021, the re-domiciliation of Trinseo S.A. from Luxembourg to Ireland pursuant to a merger by acquisition under the European Communities (Cross-Border Mergers) Regulations 2008 of Ireland (SI 157/2008), as amended, and the Luxembourg law of 10 August 2015, as amended, was completed (the “Merger”). Pursuant to the Merger: (i) Trinseo PLC, a public limited company incorporated under the laws of Ireland, by operation of law and universal succession of title, became entitled to the assets of Trinseo S.A. and assumed the liabilities of Trinseo S.A. from the effective time of the Merger (the “Effective Time”); (ii) ordinary shares of $0.01 each (nominal value) were allotted and issued by the Trinseo PLC to the shareholders of Trinseo S.A. (other than Trinseo S.A. as holder of shares in itself), on a one-for-one basis, at the Effective Time as consideration for the transfer of the assets and liabilities of Trinseo S.A.; and (iii) Trinseo S.A. ceased to exist following completion of the Merger.

C.In connection with the Merger, among other matters, at the Effective Time, the Original Plan and all awards then outstanding under the Original Plan were assumed by Trinseo PLC and the Original Plan was amended and restated on the terms set out herein and renamed the Trinseo PLC Amended And Restated 2014 Omnibus Incentive Plan (the Original Plan as so assumed, amended and restated at the Effective Time and as may, from time to time, be amended in respect of periods following the Effective Time, the “Plan”).

D.Save as otherwise expressly provided herein, the Plan shall apply to all awards granted prior to or following the Effective Time.

1.DEFINED TERMS

Exhibit A, which is incorporated by reference, defines the terms used in the Plan and sets forth certain operational rules related to those terms.

2.PURPOSE

The Plan has been established to advance the interests of the Company by providing for the grant to Participants of Stock-based Awards.

3.ADMINISTRATION

The Administrator has discretionary authority, subject only to the express provisions of the Plan, to interpret the Plan; determine eligibility for and grant Awards; determine, modify or waive the terms and conditions of any Award; determine the form of settlement of Awards (whether in cash, shares of Stock or other property); prescribe forms, rules and procedures relating to the Plan; and

Exhibit 10.1

otherwise do all things necessary or appropriate to carry out the purposes of the Plan. Determinations of the Administrator made under the Plan will be conclusive and will bind all parties.

4.LIMITS ON AWARDS UNDER THE PLAN

(a)Number of Shares. The maximum number of shares of Stock that may be delivered in satisfaction of Awards under the Plan and under the Trinseo PLC Non-Employee Equity Incentive Plan (which is a sub-plan of the Plan and is attached hereto as Appendix A) is 7,575,000 shares. Up to the total number of shares available for Awards to employee Participants may be issued in satisfaction of ISOs, but nothing in this Section 4(a) will be construed as requiring that any, or any fixed number of, ISOs be awarded under the Plan. The limits set forth in this Section 4(a) shall be construed to comply with Section 422 of the Code. For purposes of this Section 4(a), the shares of Stock withheld by the Company in payment of the exercise price or purchase price (including any nominal value payable in respect of an Award provided always that such nominal value must be paid by the Participant or some other person permitted to do so by Irish law as provided for in Section 6(a)(9)) of the Award, in satisfaction of tax withholding requirements with respect to the Award, or purchased by the Company using proceeds from Awards are prohibited from being returned back to the Plan’s share reserve for future issuance. The gross number of SAR awards granted under the Plan, as opposed to the net number of shares actually delivered under the SAR Award, will be deducted from the number of shares remaining available for issuance pursuant to the Awards granted under the Plan. For the avoidance of doubt, any shares of Stock underlying Awards settled in cash or that otherwise expire or become unexercisable without having been exercised or that are forfeited to or repurchased or redeemed by the Company due to the failure to vest may be returned to the Plan for future issuance. To the extent consistent with the requirements of Section 422 and the regulations thereunder, and with other applicable legal requirements (including applicable stock exchange requirements), Stock issued under awards of an acquired company that are converted, replaced or adjusted in connection with the acquisition shall not reduce the number of shares of Stock available for Awards under the Plan.

(b)Type of Shares. Stock delivered by the Company under the Plan may be newly issued Stock or treasury Stock acquired by the Company. No fractional shares of Stock will be delivered under the Plan.

(c)Individual Limits. The following additional limits will apply to Awards of the specified type granted, or in the case of Cash Awards, payable to any person in any calendar year:

(1)Stock Options: 900,000 shares of Stock.

(2)SARs: 900,000 shares of Stock.

(3)Awards other than Stock Options, SARs or Cash Awards: 450,000 shares of Stock.

(4)Cash Awards: $5,000,000.

In applying the foregoing limits, (i) all Awards of the specified type granted to the same person in the same calendar year will be aggregated and made subject to one limit; (ii) the limits applicable to Stock Options and SARs refer to the number of shares of Stock subject to those Awards; (iii) the share limit under clause (3) refers to the maximum number of shares of Stock that may be delivered, or the value of which could be paid in cash or other property, under an Award or Awards of the type specified in clause (3) assuming a maximum payout; and (iv) the dollar limit under

Exhibit 10.1

clause (4) refers to the maximum dollar amount payable under an Award or Awards of the type specified in clause (4) assuming a maximum payout.

5.ELIGIBILITY AND PARTICIPATION

The Administrator will select Participants from among key Employees of the Company and its Affiliates who are in a position to contribute significantly to the success of the Company and its Affiliates. Eligibility for ISOs is limited to individuals described in the first sentence of this Section 5 who are employees of the Company or of a “parent corporation” or “subsidiary corporation” of the Company as those terms are defined in Section 424 of the Code. Eligibility for Stock Options other than ISOs is limited to individuals described in the first sentence of this Section 5 who are providing direct services on the date of grant of the Stock Option to the Company or to a subsidiary of the Company that would be described in the first sentence of Treas. Regs. §1.409A-1(b)(5)(iii)(E). Non-employee Directors and consultants and vendors of the Company or Affiliates shall be eligible to participate under the Trinseo PLC Non-Employee Equity Incentive Plan (which is a sub-plan of the Plan and is attached hereto as Appendix A.

6.RULES APPLICABLE TO AWARDS

(a)All Awards.

(1)Award Provisions. The Administrator will determine the terms of all Awards, subject to the limitations provided herein. By accepting (or, under such rules as the Administrator may prescribe, being deemed to have accepted) an Award, the Participant will be deemed to have agreed to the terms of the Award and the Plan. Notwithstanding any provision of this Plan to the contrary, awards of an acquired company that are converted, replaced or adjusted in connection with the acquisition may contain terms and conditions that are inconsistent with the terms and conditions specified herein, as determined by the Administrator.

(2)Term of Plan. No Awards may be made after twenty years from the Date of Adoption, but previously granted Awards may continue beyond that date in accordance with their terms.

(3)Transferability. Neither ISOs nor, except as the Administrator otherwise expressly provides in accordance with the third sentence of this Section 6(a)(3), other Awards may be transferred other than by will or by the laws of descent and distribution. During a Participant’s lifetime, ISOs (and, except as the Administrator otherwise expressly provides in accordance with the third sentence of this Section 6(a)(3), SARs and NSOs) may be exercised only by the Participant. The Administrator may permit the gratuitous transfer (i.e., transfer not for value) of Awards other than ISOs, subject to such limitations as the Administrator may impose.

(4)Vesting, etc. The Administrator will determine the time or times at which an Award will vest or become exercisable and the terms on which a Stock Option or SAR will remain exercisable. Except in the event of the Participant’s death or disability, termination due to restructuring or redundancy, or a five percent (5%) carve-out of the number of shares of Stock that may be delivered in satisfaction of Awards under the Plan (as defined in Section 4(a)), all Awards will only vest or become exercisable after a minimum of twelve months from the grant date. Without limiting the foregoing, the Administrator may at any time accelerate the vesting or exercisability of an Award, regardless of any adverse or potentially adverse tax or other consequences resulting from such acceleration. Unless the Administrator expressly provides otherwise, however, the following rules will apply if a Participant’s Employment ceases:

Exhibit 10.1

(A)Immediately upon the cessation of the Participant’s Employment and except as provided in (B) and (C) below, each Stock Option and SAR that is then held by the Participant or by the Participant’s permitted transferees, if any, will cease to be exercisable and will terminate and all other Awards that are then held by the Participant or by the Participant’s permitted transferees, if any, to the extent not already vested will be forfeited.

(B)Subject to (C) and (D) below, all Stock Options and SARs held by the Participant or the Participant’s permitted transferees, if any, immediately prior to the cessation of the Participant’s Employment, to the extent then exercisable, will remain exercisable for the lesser of (i) a period of three months or (ii) the period ending on the latest date on which such Stock Option or SAR could have been exercised without regard to this Section 6(a)(4), and will thereupon immediately terminate.

(C)All Stock Options and SARs held by a Participant or the Participant’s permitted transferees, if any, immediately prior to the cessation of the Participant’s Employment due to his or her death or by the Company due to his or her Permanent Disability, to the extent then exercisable, will remain exercisable for the lesser of (i) a period of twelve (12) months or (ii) the period ending on the latest date on which such Stock Option or SAR could have been exercised without regard to this Section 6(a)(4), and will thereupon immediately terminate.

(D)All Stock Options and SARs (whether or not exercisable) held by a Participant or the Participant’s permitted transferees, if any, immediately prior to the cessation of the Participant’s Employment will immediately terminate upon such cessation of Employment if the termination is for Cause or occurs in circumstances that in the sole determination of the Administrator would have constituted grounds for the Participant’s Employment to be terminated for Cause.

(5)Additional Restrictions. The Administrator may cancel, rescind, withhold or otherwise limit or restrict any Award at any time if the Participant is not in compliance with all applicable provisions of the Award agreement and the Plan, or if the Participant breaches any agreement with the Company or its Affiliates with respect to non-competition, non-solicitation or confidentiality. Without limiting the generality of the foregoing, the Administrator may recover Awards made under the Plan and payments under or gain in respect of any Award in accordance with any applicable Company clawback or recoupment policy, as such policy may be amended and in effect from time to time, or as otherwise required by applicable law or applicable stock exchange listing standards, including, without limitation, Section 10D of the Securities Exchange Act of 1934, as amended.

(6)Taxes. The Company or any Affiliate shall have the authority and right to deduct or withhold or require a Participant to remit to the Company or any Affiliate, an amount sufficient to satisfy Tax-Related Items with respect to any taxable event concerning a Participant arising as a result of the Plan or to take such other action as may be necessary in the opinion of the Company or any Affiliate, as appropriate, to satisfy withholding obligations for the payment of Tax-Related Items, including but not limited to (i) withholding from the Participant’s wages or other cash compensation; (ii) withholding from the proceeds for the sale of shares of Stock underlying the Award either through a voluntary sale or a mandatory sale arranged by the Company on the Participant’s behalf; or (iii) in the Administrator’s sole discretion and in satisfaction of the foregoing requirement withhold shares of Stock otherwise issuable under an Award (or allow the return of shares of Stock ) having a fair market value equal to the sums required to be withheld. To avoid negative accounting treatment, the number of Shares which may be withheld with respect to the issuance, vesting, exercise or payment of any Award or which may be repurchased from the Participant of such Award in order to satisfy the Participant's Tax-Related Items liabilities with

Exhibit 10.1

respect to the issuance, vesting, exercise or payment of the Award may be limited to the number of shares of Stock which have a fair market value on the date of withholding or repurchase equal to the aggregate amount of such liabilities based on the maximum applicable withholding rates. No Stock shall be delivered hereunder to any Participant or other person until the Participant or such other person has made arrangements acceptable to the Company for the satisfaction of the Tax-Related Items withholdings obligations with respect to any taxable event concerning the Participant or such other person arising as a result of the Plan in a manner consistent with Irish law.

(7)Dividend Equivalents, Etc. The Administrator may provide for the payment of amounts (on terms and subject to conditions established by the Administrator) in lieu of cash dividends or other cash distributions with respect to Stock subject to an Award whether or not the holder of such Award is otherwise entitled to share in the actual dividend or distribution in respect of such Award, except for Awards of Stock Options or SARs, for which such payments shall be prohibited. Any entitlement to dividend equivalents or similar entitlements will be established and administered either consistent with an exemption from, or in compliance with, the requirements of Section 409A. Dividends or dividend equivalent amounts payable in respect of Awards shall be subject to the identical time-based vesting and performance conditions as the underlying Award and cannot be paid unless and until all vesting and performance conditions of the underlying Award are met. Dividends or dividend equivalent amounts payable in respect of Awards that are subject to restrictions may be subject to such additional limits or restrictions as the Administrator may impose, consistent with the requirements of the Articles.

(8)Rights Limited. Nothing in the Plan will be construed as giving any person the right to continued employment or service with the Company or its Affiliates, or any rights as a stockholder except as to shares of Stock actually issued under the Plan. The loss of existing or potential profit in Awards will not constitute an element of damages in the event of a termination of Employment for any reason, even if the termination is in violation of an obligation of the Company or any Affiliate to the Participant.

(9)Purchase Price. At the time of the Award, the Administrator shall determine the price, if any, to be paid by the Participant for each share of Stock  subject to the Award.  The price to be paid by the Participant shall not be less than the nominal value of a share of Stock (or such higher amount required by applicable Irish law). The purchase price of shares of Stock acquired pursuant to the Award shall be paid or redeemed by a non-Irish incorporated Subsidiary on behalf of the Participant as designated by the Administrator or by the Participant through one or more of the following methods (a) in cash or (b) in any other form of legal consideration that may be acceptable to the Administrator in its discretion and in compliance with applicable Irish law.

(10)Coordination with Other Plans. Awards under the Plan may be granted in tandem with, or in satisfaction of or substitution for awards made under other compensatory plans or programs of the Company or its Affiliates. For example, but without limiting the generality of the foregoing, awards under other compensatory plans or programs of the Company or its Affiliates may be settled in Stock (including, without limitation, Unrestricted Stock) if the Administrator so determines, in which case the shares delivered will be treated as awarded under the Plan (and will reduce the number of shares thereafter available under the Plan in accordance with the rules set forth in Section 4).

(11)Section 409A. Each Award will contain such terms as the Administrator determines, and will be construed and administered, such that the Award either qualifies for an exemption from the requirements of Section 409A or satisfies such requirements.

Exhibit 10.1

(12)Fair Market Value. In determining the fair market value of any share of Stock under the Plan, the Administrator will make the determination in good faith, and consistent with the rules of Section 422 and Section 409A when applicable.

(b)Stock Options and SARs.

(1)Time And Manner Of Exercise. Unless the Administrator expressly provides otherwise, no Stock Option or SAR will be deemed to have been exercised until the Administrator receives a notice of exercise (in form acceptable to the Administrator), which may be an electronic notice, signed (including electronic signature in form acceptable to the Administrator) by the appropriate person and accompanied by any payment required under the Award. A Stock Option or SAR exercised by any person other than the Participant will not be deemed to have been exercised until the Administrator has received such evidence as it may require that the person exercising the Award has the right to do so. The Administrator may impose conditions on the exercisability of Awards, including limitations on the time periods during which Awards may be exercised or settled.

(2)Exercise Price. The exercise price (or the base value from which appreciation is to be measured) of each Award requiring exercise will be no less than the higher of (a) the nominal value of the Stock subject to the Award and (b) 100% (or in the case of an ISO granted to a ten-percent shareholder within the meaning of subsection (b)(6) of Section 422, 110%) of the fair market value of the Stock subject to the Award, determined as of the date of grant, or such higher amount as the Administrator may determine in connection with the grant.

(3)No Repricing. Except in connection with a corporate transaction involving the Company (which term shall include, without limitation, any stock dividend, stock split, extraordinary cash dividend, recapitalization, reorganization, merger, consolidation, split-up, spin-off, combination, or exchange of shares) or as otherwise contemplated by Section 7 of the Plan, the terms of outstanding Stock Options or SARs, as applicable, may not be amended to reduce the exercise prices of such Stock Options or the base values from which appreciation under such SARs are to be measured other than in accordance with the stockholder approval requirements of the New York Stock Exchange. Unless otherwise submitted to and approved by the Company’s shareholders, any substitution or buyout of Stock Options or SARs for cash, as applicable, shall be prohibited when the exercise price for such Stock Option is below the current fair market value or when the base value from which appreciation under such SARs are to be measured is below the current fair market value.

(4)Payment Of Exercise Price. Where the exercise of an Award is to be accompanied by payment, payment of the exercise price will be by cash or check acceptable to the Administrator or by such other legally permissible means, if any, as may be acceptable to the Administrator.

(5)Maximum Term. Stock Options and SARs will have a maximum term not to exceed ten (10) years from the date of grant (or five (5) years from the date of grant in the case of an ISO granted to a ten-percent shareholder described in Section 6(b)(2) above); provided, however, that, if a Participant still holding an outstanding but unexercised NSO or SAR ten (10) years from the date of grant (or, in the case of an NSO or SAR with a maximum term of less than ten (10) years, such maximum term) is prohibited by applicable law or a written policy of the Company applicable to similarly situated employees from engaging in any open-market sales of Stock, and if at such time the Stock is publicly traded (as determined by the Administrator), the maximum term of such Award will instead be deemed to expire on the thirtieth (30th) day following the date

Exhibit 10.1

the Participant is no longer prohibited from engaging in such open market sales.

7.EFFECT OF CERTAIN TRANSACTIONS

(a)Mergers, etc. Except as otherwise provided in an Award agreement, the following provisions will apply in the event of a Covered Transaction:

(1)Assumption or Substitution. If the Covered Transaction is one in which there is an acquiring or surviving entity, the Administrator may (but, for the avoidance of doubt, need not) provide (i) for the assumption or continuation of some or all outstanding Awards or any portion thereof or (ii) for the grant of new awards in substitution therefor by the acquiror or survivor or an affiliate of the acquiror or survivor.

(2)Cash-Out of Awards. Subject to Section 7(a)(5) below the Administrator may (but, for the avoidance of doubt, need not) provide for payment (a “cash-out”), with respect to some or all Awards or any portion thereof, equal in the case of each affected Award or portion thereof to the excess, if any, of (A) the fair market value of one share of Stock (as determined by the Administrator in its reasonable discretion) times the number of shares of Stock subject to the Award or such portion, over (B) the aggregate exercise or purchase price, if any, under the Award or such portion (in the case of an SAR, the aggregate base value above which appreciation is measured), in each case on such payment terms (which need not be the same as the terms of payment to holders of Stock) and other terms, and subject to such conditions, as the Administrator determines; it being understood that if the exercise or purchase price (or base value) of an Award is equal to or greater than the fair market value of one share of Stock, the Award may be cancelled with no payment due hereunder.

(3)Acceleration of Certain Awards. Subject to Section 7(a)(5) below, the Administrator may (but, for the avoidance of doubt, need not) provide that any Award requiring exercise will become exercisable, in full or in part and/or that the delivery of any shares of Stock remaining deliverable under any outstanding Award of Stock Units (including Restricted Stock Units and Performance Awards to the extent consisting of Stock Units) will be accelerated in full or in part, in each case on a basis that gives the holder of the Award a reasonable opportunity, as determined by the Administrator, following exercise of the Award or the delivery of the shares, as the case may be, to participate as a stockholder in the Covered Transaction.

(4)Termination of Awards Upon Consummation of Covered Transaction. Except as the Administrator may otherwise determine in any case, each Award will automatically terminate (and in the case of outstanding shares of Restricted Stock, will automatically be forfeited) upon consummation of the Covered Transaction, other than Awards assumed pursuant to Section 7(a)(1) above.

(5)Additional Limitations. Any share of Stock and any cash or other property delivered pursuant to Section 7(a)(2) or Section 7(a)(3) above with respect to an Award may, in the discretion of the Administrator, contain such restrictions, if any, as the Administrator deems appropriate to reflect any performance or other vesting conditions to which the Award was subject and that did not lapse (and were not satisfied) in connection with the Covered Transaction. For purposes of the immediately preceding sentence, a cash-out under Section 7(a)(2) above or acceleration under Section 7(a)(3) above will not, in and of itself, be treated as the lapsing (or satisfaction) of a performance or other vesting condition. In the case of Restricted Stock that does not vest and is not forfeited in connection with the Covered Transaction, the Administrator may require that any amounts delivered, exchanged or otherwise paid in respect of such Stock in

Exhibit 10.1

connection with the Covered Transaction be placed in escrow or otherwise made subject to such restrictions as the Administrator deems appropriate to carry out the intent of the Plan.

(b)Changes in and Distributions With Respect to Stock.

(1)Basic Adjustment Provisions. In the event of a stock dividend, stock split or combination of shares (including a reverse stock split), recapitalization or other change in the Company’s capital structure that constitutes an equity restructuring within the meaning of FASB ASC 718, the Administrator will make appropriate adjustments to the maximum number of shares of Stock that may be delivered under the Plan, to the maximum number of shares of Stock that may be delivered in satisfaction of ISOs under the Plan, and to the maximum share limits described in Section 4(c) and will also make appropriate adjustments to the number and kind of shares of stock or securities subject to Awards then outstanding or subsequently granted, any exercise or purchase prices (or base values) relating to Awards and any other provision of Awards affected by such change.

(2)Certain Other Adjustments. The Administrator may also make adjustments of the type described in Section 7(b)(1) above to take into account distributions to stockholders other than those provided for in Section 7(a) and 7(b)(1), or any other event, if the Administrator determines that adjustments are appropriate to avoid distortion in the operation of the Plan, having due regard for the qualification of ISOs under Section 422, and the requirements of Section 409A.

(3)Continuing Application of Plan Terms. References in the Plan to shares of Stock will be construed to include any stock or securities resulting from an adjustment pursuant to this Section 7.

8.LEGAL CONDITIONS ON DELIVERY OF STOCK

The Company will not be obligated to deliver any shares of Stock pursuant to the Plan or to remove any restriction from shares of Stock previously delivered under the Plan until: (i) the Company is satisfied that all legal matters in connection with the issuance and delivery of such shares have been addressed and resolved; (ii) if the outstanding Stock is at the time of delivery listed on any stock exchange or national market system, the shares to be delivered have been listed or authorized to be listed on such exchange or system upon official notice of issuance; and (iii) all conditions of the Award have been satisfied or waived. The Company may require, as a condition to exercise of the Award, such representations or agreements as counsel for the Company may consider appropriate to avoid violation of the Securities Act of 1933, as amended, or any applicable state or non-U.S. securities law. Any Stock required to be issued to Participants under the Plan will be evidenced in such manner as the Administrator may deem appropriate, including book-entry registration or delivery of stock certificates. In the event that the Administrator determines that Stock certificates will be issued to Participants under the Plan, the Administrator may require that certificates evidencing Stock issued under the Plan bear an appropriate legend reflecting any restriction on transfer applicable to such Stock, and the Company may hold the certificates pending lapse of the applicable restrictions.

9.AMENDMENT AND TERMINATION

The Administrator may at any time or times amend the Plan or any outstanding Award for any purpose which may at the time be permitted by law, and may at any time terminate the Plan as to any future grants of Awards; provided, that, except as otherwise expressly provided in the Plan, the Administrator may not, without the Participant’s consent, alter the terms of an Award so as to

Exhibit 10.1

affect materially and adversely the Participant’s rights under the Award, unless the Administrator expressly reserved the right to do so at the time the Award was granted. Any amendments to the Plan will be conditioned upon stockholder approval only to the extent, if any, such approval is required by law (including the Code and applicable stock exchange requirements), as determined by the Administrator.

10.OTHER COMPENSATION ARRANGEMENTS

The existence of the Plan or the grant of any Award will not in any way affect the Company’s right to award a person bonuses or other compensation in addition to Awards under the Plan.

11.MISCELLANEOUS

(a)Waiver of Jury Trial. By accepting an Award under the Plan, each Participant waives any right to a trial by jury in any action, proceeding or counterclaim concerning any rights under the Plan and any Award, or under any amendment, waiver, consent, instrument, document or other agreement delivered or which in the future may be delivered in connection therewith, and agrees that any such action, proceedings or counterclaim will be tried before a court and not before a jury. By accepting an Award under the Plan, each Participant certifies that no officer, representative, or attorney of the Company has represented, expressly or otherwise, that the Company would not, in the event of any action, proceeding or counterclaim, seek to enforce the foregoing waivers. Notwithstanding anything to the contrary in the Plan, nothing herein is to be construed as limiting the ability of the Company and a Participant to agree to submit disputes arising under the terms of the Plan or any Award made hereunder to binding arbitration or as limiting the ability of the Company to require any eligible individual to agree to submit such disputes to binding arbitration as a condition of receiving an Award hereunder.

(b)Limitation of Liability. Notwithstanding anything to the contrary in the Plan, neither the Company, nor any Affiliate, nor the Administrator, nor any person acting on behalf of the Company, any Affiliate, or the Administrator, will be liable to any Participant or to the estate or beneficiary of any Participant or to any other holder of an Award by reason of any acceleration of income, or any additional tax (including any interest and penalties), asserted by reason of the failure of an Award to satisfy the requirements of Section 422 or Section 409A or by reason of Section 4999 of the Code, or otherwise asserted with respect to the Award.

12.MISCELLANEOUS ESTABLISHMENT OF SUB-PLANS

The Administrator may from time to time establish one or more sub-plans under the Plan for purposes of satisfying applicable securities, or other regulatory or tax laws of various jurisdictions. The Administrator will establish such sub-plans by adopting supplements to the Plan setting forth (i) such limitations on the Administrator’s discretion under the Plan as it deems necessary or desirable and (ii) such additional terms and conditions not otherwise inconsistent with the Plan as it deems necessary or desirable. All supplements so established will be deemed to be part of the Plan, but each supplement will apply only to Participants within the affected jurisdiction (as determined by the Administrator).

13.GOVERNING LAW

(a)Certain Requirements of Corporate Law. Awards will be granted and administered consistent with the requirements of applicable law of Ireland relating to the issuance of stock and the consideration to be received therefor, and with the applicable requirements of the stock

Exhibit 10.1

exchanges or other trading systems on which the Stock is listed or entered for trading, in each case as determined by the Administrator.

(b)Other Matters. Except as otherwise provided by the express terms of an Award agreement, under a sub-plan described in Section 12 or as provided in Section 13(a) above, the provisions of the Plan and of Awards under the Plan and all claims or disputes arising out of or based upon the Plan or any Award under the Plan or relating to the subject matter hereof or thereof will be governed by and construed in accordance with the domestic substantive laws of the State of Pennsylvania without giving effect to any choice or conflict of laws provision or rule that would cause the application of the domestic substantive laws of any other jurisdiction.

(c)Jurisdiction. By accepting an Award, each Participant will be deemed to (a) have submitted irrevocably and unconditionally to the jurisdiction of the federal and state courts located within the geographic boundaries of the United States District Court for the District of Pennsylvania for the purpose of any suit, action or other proceeding arising out of or based upon the Plan or any Award; (b) agree not to commence any suit, action or other proceeding arising out of or based upon the Plan or an Award, except in the federal and state courts located within the geographic boundaries of the United States District Court for the District of Pennsylvania; and (c) waive, and agree not to assert, by way of motion as a defense or otherwise, in any such suit, action or proceeding, any claim that it is not subject personally to the jurisdiction of the above-named courts that its property is exempt or immune from attachment or execution, that the suit, action or proceeding is brought in an inconvenient forum, that the venue of the suit, action or proceeding is improper or that the Plan or an Award or the subject matter thereof may not be enforced in or by such court.

Exhibit 10.1

EXHIBIT A

Definition of Terms

The following terms, when used in the Plan, will have the meanings and be subject to the provisions set forth below:

“Administrator”: The Compensation Committee, except that the Compensation Committee may delegate (i) to one or more of its members (or one or more other members of the Board (including the full Board)) such of its duties, powers and responsibilities as it may determine; (ii) to one or more officers of the Company the power to grant Awards to the extent permitted by applicable law; and (iii) to such Employees or other persons as it determines such ministerial tasks as it deems appropriate. In the event of any delegation described in the preceding sentence, the term “Administrator” will include the person or persons so delegated to the extent of such delegation.

“Affiliate”: Any corporation or other entity that stands in a relationship to the Company that would result in the Company and such corporation or other entity being treated as one employer under Section 414(b) and Section 414(c) of the Code, provided that, for purposes of determining treatment as a single employer under Section 414(b) and Section 414(c) of the Code, “50%” shall replace “80%” in the applicable stock ownership requirements under such sections of the Code and the regulations thereunder.

“Articles”: The articles of association of the Company.

“Award”: Any or a combination of the following:

(i)Stock Options.

(ii)SARs.

(iii)Restricted Stock.

(iv)Unrestricted Stock.

(v)Stock Units, including Restricted Stock Units.

(vi)Performance Awards.

(vii)Cash Awards.

(viii)Awards (other than Awards described in (i) through (vii) above) that are convertible into or otherwise based on Stock.

“Board”: The Board of Directors of the Company.

“Cash Award”: An Award denominated in cash.

“Cause”: In the case of any Participant who is party to an employment or severance-benefit agreement that contains a definition of “Cause,” the definition set forth in such agreement will apply with respect to such Participant under the Plan for so long as such agreement is in effect. In the case of any other Participant, “Cause” will mean, as determined by the Administrator in its

Exhibit 10.1

reasonable judgment, (i) a substantial failure of the Participant to perform the Participant’s duties and responsibilities to the Company or subsidiaries or substantial negligence in the performance of such duties and responsibilities; (ii) the commission by the Participant of a felony or a crime involving moral turpitude; (iii) the commission by the Participant of theft, fraud, embezzlement, material breach of trust or any material act of dishonesty involving the Company or any of its subsidiaries; (iv) a significant violation by the Participant of the code of conduct of the Company or its subsidiaries or of any material policy of the Company or its subsidiaries, or of any statutory or common law duty of loyalty to the Company or its subsidiaries; (v) material breach of any of the terms of the Plan or any Award made under the Plan, or of the terms of any other agreement between the Company or subsidiaries and the Participant; or (vi) other conduct by the Participant that could reasonably be expected to be harmful to the business, interests or reputation of the Company.

“Code”: The U.S. Internal Revenue Code of 1986 as from time to time amended and in effect, or any successor statute as from time to time in effect.

“Compensation Committee”: The Compensation Committee of the Board.

“Company”: Trinseo PLC, a company incorporated in Ireland or, where the context requires,

with respect to periods prior to the Effective Time, Trinseo S.A.

“Covered Transaction”: Any of (i) a consolidation, merger, or similar transaction or series of related transactions, including a sale or other disposition of stock, in which the Company is not the surviving corporation or that results in the acquisition of all or substantially all of the Company’s then outstanding ordinary shares by a single person or entity or by a group of persons and/or entities acting in concert, (ii) a sale or transfer of all or substantially all the Company’s assets, or (iii) a dissolution or liquidation of the Company. Where a Covered Transaction involves a tender offer that is reasonably expected to be followed by a merger described in clause (i) (as determined by the Administrator), the Covered Transaction will be deemed to have occurred upon consummation of the tender offer.

“Date of Adoption”: The earlier of the dates (both prior to the Effective Time) that the Plan was approved by the Company’s shareholders or adopted by the Board, as determined by the Compensation Committee.

“Director”: A member of the Board.

“Employee”: Any person who is employed by the Company or an Affiliate.

“Employment”: A Participant’s employment or other service relationship with the Company and its Affiliates. Employment will be deemed to continue, unless the Administrator expressly provides otherwise, so long as the Participant is employed by, or otherwise is providing services in a capacity described in Section 5 to the Company or an Affiliate. If a Participant’s employment or other service relationship is with an Affiliate and that entity ceases to be an Affiliate, the Participant’s Employment will be deemed to have terminated when the entity ceases to be an Affiliate unless the Participant transfers Employment to the Company or its remaining Affiliates. Notwithstanding the foregoing and the definition of “Affiliate” above, in construing the provisions of any Award relating to the payment of “nonqualified deferred compensation” (subject to Section 409A) upon a termination or cessation of Employment, references to termination or cessation of employment, separation from service, retirement or similar or correlative terms will be construed to require a “separation from service” (as that term is defined in Section 1.409A- 1(h) of the U.S.

Exhibit 10.1

Treasury Regulations, after giving effect to the presumptions contained therein) from the Company and from all other corporations and trades or businesses, if any, that would be treated as a single “service recipient” with the Company under Section 1.409A-1(h)(3) of the U.S. Treasury Regulations. The Company may, but need not, elect in writing, subject to the applicable limitations under Section 409A, any of the special elective rules prescribed in Section 1.409A- 1(h) of the U.S. Treasury Regulations for purposes of determining whether a “separation from service” has occurred.  Any such written election will be deemed a part of the Plan.

“ISO”: A Stock Option intended to be an “incentive stock option” within the meaning of Section 422. Each Stock Option granted pursuant to the Plan will be treated as providing by its terms that it is to be an NSO unless, as of the date of grant, it is expressly designated as an ISO.

“NSO”: A Stock Option that is not intended to be an “incentive stock option” within the meaning of Section 422.

“Participant”: A person who is granted an Award under the Plan.

“Performance Award”: An Award subject to Performance Criteria.

“Performance Criteria”: Specified criteria, other than the mere continuation of Employment or the mere passage of time, the satisfaction of which is a condition for the grant, exercisability, vesting or full enjoyment of an Award. A Performance Criterion will mean an objectively determinable measure or measures of performance relating to any or any combination of the following (measured either absolutely or by reference to an index or indices and determined either on a consolidated basis or, as the context permits, on a divisional, subsidiary, line of business, project or geographical basis or in combinations thereof): sales; revenues; assets; expenses; earnings before or after deduction for all or any portion of interest, taxes, depreciation, amortization or equity expense, whether or not on a continuing operations or an aggregate or per share basis; return on equity, investment, capital, capital employed or assets; one or more operating ratios; operating income or profit, including on an after-tax basis; net income; borrowing levels, leverage ratios or credit rating; market share; capital expenditures; cash flow; stock price; stockholder return; sales of particular products or services; customer acquisition or retention; acquisitions and divestitures (in whole or in part); joint ventures, strategic alliances, licenses or collaborations; spin-offs, split-ups and the like; reorganizations; recapitalizations, restructurings, financings (issuance of debt or equity) or refinancings; manufacturing or process development; or environmental health and/or safety metrics. A Performance Criterion and any targets with respect thereto determined by the Administrator need not be based upon an increase, a positive or improved result or avoidance of loss. The Administrator may provide, by the deadline that otherwise applies to the establishment of the terms of any Award intended to qualify for such exception, that one or more of the Performance Criteria applicable to such Award will be adjusted in an objectively determinable manner to reflect events (for example, the impact of charges for restructurings, discontinued operations, mergers, acquisitions, extraordinary items, and other unusual or non- recurring items, and the cumulative effects of tax or accounting changes, each as defined by U.S. or international generally accepted accounting principles) occurring during the performance period that affect the applicable Performance Criterion or Criteria.

“Permanent Disability”: In the case of any Participant who is party to an employment or severance-benefit agreement that contains a definition of “Permanent Disability” (or similar term), the definition set forth in such agreement will apply with respect to such Participant under the Plan for so long as such agreement is in effect. In the case of any other Participant, “Permanent Disability” shall mean a disability that would entitle a Participant to long-term disability benefits

Exhibit 10.1

under the Company’s long-term disability plan to which the Participant participates. Notwithstanding the foregoing, however, in the case of any Award that is subject to Section 409A and is payable upon a Participant’s Permanent Disability, the Participant shall be treated as having a Permanent Disability only if the Participant’s condition also satisfies the definition of “disability” in Treasury Regulation 1.409A-3(i)(4).

“Restricted Stock”: Stock subject to restrictions requiring that it be redelivered or offered for sale to the Company if specified conditions are not satisfied.

“Restricted Stock Unit”: A Stock Unit that is, or as to which the delivery of Stock or cash in lieu of Stock is, subject to the satisfaction of specified performance or other vesting conditions.

“SAR”: A right entitling the holder upon exercise to receive an amount (payable in cash or in shares of Stock of equivalent value) equal to the excess of the fair market value of the shares of Stock subject to the right over the base value from which appreciation under the SAR is to be measured.

“Section 409A”: Section 409A of the Code.

“Section 422”: Section 422 of the Code.

“Stock”: Ordinary shares of the Company, nominal value $0.01 per share and “stockholder” shall be interpreted accordingly where referring to holders of Stock in the Company.

“Stock Option”: An option entitling the holder to acquire shares of Stock upon payment of the exercise price.

“Stock Unit”: An unfunded and unsecured promise, denominated in shares of Stock, to deliver Stock or cash measured by the value of Stock in the future.

“Tax-Related Items”means (i) federal, state, and local taxes and taxes imposed by any jurisdiction (including but not limited to, income tax, social security or insurance contributions, payroll tax, fringe benefits tax, payment on account, employment tax obligations, stamp taxes, and any other taxes that may be due) required by law to be withheld and (ii) any employer tax liability shifted to a Participant.

“Unrestricted Stock”: Stock not subject to any restrictions under the terms of the Award.

Exhibit 10.1

TRINSEO PLC

NON-EMPLOYEE EQUITY INCENTIVE PLAN

(THE “NON-EMPLOYEE PLAN”)

Section 1. Introduction.

(a) The Non-Employee Plan is a sub-plan of the Trinseo PLC Amended & Restated 2014 Omnibus Incentive Plan (the “Plan”) and permits the grant of Awards to non-employee directors, consultants and vendors of the Company or Affiliate who are not employees (as at the time of the relevant grant) of any such company (each, a “Participant”).

(b) For the avoidance of doubt, the Non-Employee Plan (i) shall not prejudice the status of the Plan as an employees’ share scheme within the meaning of section 64 of the Companies Act 2014 and (ii) operates separately from the Plan.

Section 2. Definitions and Interpretation

(a) In the Non-Employee Plan, words and expressions used in the Plan shall, unless otherwise specified below, apply in relation to Awards granted under the Non-Employee Plan.

(b) Except as modified in the Non-Employee Plan, all the provisions of the Plan relevant to Awards shall be incorporated into the Non-Employee Plan as if fully set out herein so as to be part of the Non-Employee Plan.

(c) These rules of the Non-Employee Plan take precedence if there is any inconsistency between them and the rules of the Plan.

(d) In these rules of the Non-Employee Plan, whenever the terms “Employee” or “Employment” are otherwise used in the context of matters following the grant of an Award, they shall be construed in the context of that person being a non-employee director, consultant or vendor, and termination of Employment means the Participant ceasing to be a non-employee director, consultant or vendor of the Company or an Affiliate; provided that, for avoidance of doubt, a Termination of Service will be deemed to occur if an Affiliate of which the Participant is a consultant or vendor ceases to be an Affiliate, unless they remain a consultant or vendor of the Company or another Affiliate.